What's the benefit of giving the mage a mage amulet besides earning a shard?

if you're lucky, you can receive a tome which can be used on one of your pets to boost their stats, or sold for a nice amount of money.

Oh, really? That's how you get them then. Thanks for your response~

I just learned something without meaning to! Thank you!

the odds of getting a Tome are slightly less one in six by my analysis. I personally think, but cannot prove, that the random seed is 'sticky' and it helps to redeem a large number of Amulets at any one time.